Parameters are limits that constitute the nature or definition of someone or something. If one were to describe the parameters of an unused composition notebook, then one would set the following parameters: a book with lined pages so as to allow the owner to write in it, holding no writing on those pages. If any one of the previous parameters were changed, a person would not possess an unused composition notebook. If there is a printed text from a publisher, then one would have a book (perhaps Moby Dick or Huckleberry Finn) but it would not be a composition notebook. If someone wrote on the pages of the notebook, it would still be a notebook but not an unused notebook.
Parameters are set for everything in life. Christianity is no different. What constitutes the core parameters of one who claims to be a Christian? C. S. Lewis wrote about Mere Christianity, that is, Christianity at its most basic form. But what about the mere Christian? What are the core fundamentals that constitute the life of a Christian? The apostle John answers that question in his first letter. Within the text of 1 John, the reader will find five parameters of Christianity: holiness, love, truth, perseverance, and testimony.
Parameter of Christian Holiness (1 John 3:9; 5:18).
The first parameter that John sets is that of holiness. John writes, “No one of God makes a practice of sinning, for God’s seed abides in him, and he cannot keep on sinning because he has been born of God (1 John 3:9). Some have misinterpreted this text to claim that the Christian will never sin. Popular antitheists seek out a mistake in a person calling oneself a Christian. When the antagonist finds a fault, which they are sure to do, they will claim, “See! You did wrong! You are a sinner, not a saint!” However, John does not claim that a Christian will never fall or make a mistake.
John teaches that the Christian will seek to live a righteous life and will not be seek a life of rebellion. Daniel Akin notes that “The perfect participle (gegennēmenos) implies not only a single past act of spiritual new birth but also the ongoing effects of being born of God” (Akin 2001, 147-148). This falls in line with John’s use of the term seed. “The seed refers to one of three options: (1) the Word of God, (2) the Holy Spirit, or (3) the regenerate spirit when one is born again” (Walls and Anders 1999, 195).
Therefore, a true Christian will not live a life of rebellion against God. Rather, the genuine Christian will embrace God’s standards and God’s ways. For such a one realizes that God’s thoughts and ways are much higher than their own (Isaiah 55:9).
Parameter of Christian Love (1 John 4:7).
John provides another parameter of the genuine Christian, that of love. John writes that “Beloved, let us love one another, for love is from God, and whoever loves has been born of God and knows God. Anyone who does not love does not know God, because God is love” (1 John 4:7-8). What is the basis of such love? John notes that “if God so loved us, we also ought to love one another” (1 John 4:11). The Christian has experienced the love of God. Therefore, it is expected that the Christian demonstrate that same kind of love to others. A person’s vertical relationship with God should affect the person’s horizontal relationship that they hold with others. Kruse states that “When the author says that ‘God is love’, he is not making an ontological statement describing what God is in his essence; rather, he is, as the following verses (4:9–10) reveal, speaking about the loving nature of God revealed in saving action on behalf of humankind” (Kruse 2000, 157). I disagree with Kruse’s assessment of John’s benevolent ontological nature of God. For the basis of a believer’s love is based on the nature of God’s love and the demonstration of God’s love to the believer. Nevertheless, I do agree with Kruse’s assessment of John’s emphasis on God’s saving action on behalf of humanity. Thus, the genuine believer must possess a love for others. Obviously that love may be tested and there will be those who are difficult to love. This love is a choice, a choice based on one’s obedience unto God.
Parameter of Christian Truth (1 John 5:1).
Third, John provides the parameter of truth. John notes that “Everyone believes that Jesus is the Christ has been born of God, and everyone who loves the Father loves whoever has been born of him” (1 John 5:1). As has been noted ample times by this author, theology matters. What a person believes shapes the way the person lives. John boldly proclaims that one should “test the spirits to see whether they are from God…By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God” (1 John 4:1-2). Going back to Peter’s confession, Peter noted of Jesus, “You are the Christ, the Son of the living God” (Matthew 16:16). Thus, the core fundamentals of Christianity must be accepted by the Christian to still be considered a Christian. Those core fundamentals are found in the Apostle’s Creed:
“I believe in God, the Father Almighty, Creator of heaven and earth; and in Jesus Christ, His only Son, our Lord: Who was conceived by the Holy Spirit, born of the Virgin Mary; suffered under Pontius Pilate, was crucified, died and was buried. He descended into hell; the third day He rose again from the dead; He ascended into heaven, is seated at the right hand of God the Father Almighty; from thence He shall come to judge the living and the dead. I believe in the Holy Spirit, the Holy Catholic Church (meaning universal church, not the denomination), the communion of saints, the forgiveness of sins, the resurrection of the body, and life everlasting. Amen” (Apostles Creed).
This constitutes mere Christianity. If these core fundamentals are not held, then one is found outside the theological boundaries of the Christian faith.
Parameter of Christian Perseverance (1 John 5:4).
John also notes that the Christian will be found within the parameter of perseverance. John writes, “For everyone who has been born of God overcomes the world. And this is the victory that has overcome the world—our faith” (1 John 5:4). In his Parable of the Sower, Jesus describes the true Christian as one who has heard the gospel, accepted the gospel, and one in which the gospel has taken root. The true believer will persevere. A person who remains wishy-washy in the faith is one whose legitimacy could be questioned. A person who says one day, “I wish to follow Jesus” and the next “I wish to live only for myself” is not one who will persevere and is rather one who is indecisive in their discipleship. The believer will come to accept Christ and follow him with steadfast perseverance. This is not to say that one cannot backslide, as I myself have done. But, rather one’s overall life will be a story of an overarching faithfulness from the point that the person met Christ until the day of that person’s death.
Parameter of Christian Testimony (1 John 5:9-10).
Finally, Jesus notes that the Christian will have evidence of a Christian testimony. John writes, “If we receive the testimony of men, the testimony of God is greater, for this is the testimony of God that he has borne concerning his Son. Whoever believes in the Son of God has the testimony in himself. Whoever does not believe God has made him a liar, because he has not believed in the testimony that God has borne concerning his Son” (1 John 5:9-10). What is the “testimony of God?” Different scholars hold differing perspectives. Kruse writes that “it to be identified with the testimony of the eyewitnesses, God speaking through them. This last alternative is preferable because the content of God’s testimony described in 1 John 5:11 is that God has given us eternal life in his Son, which is the central feature of the testimony of the eyewitnesses alluded to in 1 John 1:1–4” (Kruse 2000, 181). Daniel Akin thinks that “The most likely answer is that John is referring back to the threefold testimony in v. 8. This interpretation fits with the perfect tense of the verb (memarturēken, “he has testified”). God has testified concerning his Son in the past through the Spirit, water, and blood, and this testimony is still valid today” (Akin 2001, 200). I agree with Akin, however I would emphasize that the “testimony of God” refers more to the inner witness of the Holy Spirit. Going back to the testimony of Simon Peter, Jesus said after Peter’s proclamation that “Blessed are you, Simon Bar-Jonah! For flesh and blood has not revealed this to you, but my Father who is in heaven” (Matthew 16:17). Seeing that the Holy Spirit is the one who convicts and compels people to faith (John 16:8ff), then I would say that the “testimony of God” refers to this inner witness of God through the Holy Spirit. Thus, a believer should have the testimony of God in one’s life.
Christianity holds particular parameters. A lot of people can claim a lot of things about themselves. However, there are certain truths that must exist in a person’s life to legitimately be considered a child of God. A person must strive to live a life of holiness before God. It is impossible for one to do so on their own merit, but only through the empowerment of God. Secondly, a person must be filled with compassion and love. Third, a person must stand upon the truth of God’s word. Fourth, a person must not hold a flimsy, whimsical sort of faith. Rather, one’s faith must be a decisive, steadfast kind of faith. Lastly, one must have the inner witness of the Holy Spirit in one’s life. While we all fall and falter every day, it must be remembered that these attributes are those that are examined over the course of a person’s life. John’s parameters serve as a good test for all of us to gauge how close we are to the person that God has called us to be.
Akin, Daniel L. 1, 2, 3 John. Volume 38. The New American Commentary. Nashville: Broadman & Holman Publishers, 2001.
Kruse, Colin G. The Letters of John. The Pillar New Testament Commentary. Grand Rapids; Leicester, England: W.B. Eerdmans Pub.; Apollos, 2000.
Walls, David, and Max Anders. I & II Peter, I, II & III John, Jude. Volume 11. Holman New Testament Commentary. Nashville: Broadman & Holman Publishers, 1999.
 Unless otherwise noted, all Scripture in this article comes from the English Standard Version (Wheaton: Crossway, 2001).